ABB发电机用断路器HEC7-8英文.pdfVIP

Technologies for the Utility Industry SF generator circuit- 6 breaker system for short-circuit currents up to 200 kA Lukas Zehnder, Jochen Kiefer, Dieter Braun, Thomas Schoenemann Generator circuit-breakers are the ‘big boys’ of the breaker world; they have to be. A fault of up to 200 kA somewhere in the field is bad enough, but close to a generator it can lead to an event of literally seismic proportions – the fault current can be of such a magnitude that the induced magnetic forces cause solid steel shafts to bend and crash. ABB HEC 7/8 SF 6 breakers are designed for this demanding task. They can handle anything even the world’s biggest power stations can throw at them. But just how do you break such a huge current so close to the generator? And how can the breaker effectively deal with the arc that is produced? he past twenty years have seen guishing medium in the 1980s to the cooling) and able to handle short-circuit T rapid change in the generator newest breakers, described in this breaking currents of up to 200 kA. circuit-breaker field, from the first article, rated at 24,000 A (naturally Thanks to these developments, breaker to use SF6 gas as an arc-extin- cooled) and 38,000 A (with forced air modern special-purpose generator 34 ABB Review 3/2002 circuit-breakers using SF6 gas as arc- switches (for gas turbine and hydro- The overall availability of the power extinguishing medium are now available power plants) and braking switches plant auxiliary equipment is increased. for generating units with ratings up to (for hydropower plants) can also be Synchronizing at the generator 1500 MW.